Photosynthesis From Light to · PDF file... to produce usable chemical energy for their functions. Without organisms that make ... Photosynthesis & Cellular Respiration ... sunlight

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Photosynthesis – From Light to Food

How is energy acquired and used by organisms? Why? The cells of all organisms –from algae to whales -- need chemical energy for all of their

processes. Some organisms, such as diatoms and plants, absorb energy from the sun. Some of that

energy is stored in sugars. Cells break down sugars to produce usable chemical energy for their

functions. Without organisms that make sugars, living things on Earth could not survive.

Group Instructions: When responding to each question, one group member should be assigned the task

of reading the question aloud for the rest of the group. Rotate the reading among the group members

throughout the assignment so that everyone gets several turns. Remember, allow everyone the chance to

respond, and respect each other’s ideas, feelings, and answers.

Model 1

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1. Name two living (biotic) organisms you see clearly in Model 1.

2. Explain how each organism in Model 1 gets the energy it needs to live.

a. The deer gets energy by…

b. The flowers get energy from…

3. The flowers are _________________________ and the deer is a ____________________________.

producers/consumers producer/consumer

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Biology POGIL Activity Page 2

Photosynthesis & Cellular Respiration – How is energy acquired and used by organisms?

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Look at and discuss Model 2. Label the PRODUCERS and CONSUMERS in the picture.

Model 2

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Compare and contrast the terms producers and consumers by listing at least 2 things they have in

common and at least 2 things they don’t have in common.

4.

PRODUCERS CONSUMERS

5. Do you think that the deer only uses the energy that is made by the plant using sunlight? Explain.




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6. How does the plant provide for the deer, other than as a source of food?

7. What is the name given to the process whereby plants use sunlight to make food?

8. What steps do you think are involved in photosynthesis?

Think of a time when you may have helped your mother or someone else bake a cake and discuss with

your group what important pieces of information are needed before starting to make a cake.

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9. A recipe is a set of instructions needed to make a food dish along with a list of ingredients needed to

make it. Do you think it’s important for the recipe to include how much of each ingredient you

need? Why or why not?

10.Once you mix all of the ingredients according to the recipe instructions, what still has to be done to

the mixture to make it look like a cake?

11. Did it take energy to mix all of the ingredients together? If so, where did that energy come from?

12. Did it take energy to bake the cake? If so, where did that energy come from?




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13. Does it take energy to eat the cake? If so, where did that energy come from?

Reactants are the materials you use to make something new. The reactants often change into something

else once they are combined and many times don’t look the same as they did before. Products are the

materials that are made as a result of combining the reactants.

14. Think back to our cake example. What are some of the materials (reactants) needed to make the

cake? What product or products were made at the end?

REACTANTS PRODUCTS

PHOTOSYNTHESIS

Believe it or not photosynthesis helps keeps you alive. It is one of the most important processes on

Earth! Humans and plants are dependent on each other for survival. Can you figure out what

photosynthesis means just by reviewing its word parts? The prefix photo means “light” and the

synthesis means “putting together.”

15. Write your own definition for the word photosynthesis below.

But did you know that plants don’t make food for us to eat, but they use sunlight to make food for

themselves? Even though humans and other organisms eat plants for energy, that is not who they are

making the food for. Plants need to eat, too, to say alive. So, you could say that the process of

photosynthesis is like a plant cooking for itself. Many creatures just happen to like to eat plants and take

some of the energy as well. What’s even more wonderful, than plants providing us with yummy food

fuel, is that through photosynthesis, plants also provide us with oxygen, which we can’t live without.

Again, plants don’t make it on purpose just for us to breathe; it just happens to be what is made as a

result of combining the reactants together. Scientists call this a by-product. It’s kind of like when you

burn a piece of paper with a match and ash and smoke form which are both by-products. Oxygen just

resulted from the chemical change. The plant will use some of it to help break down glucose when it’s

ready to eat, very much like when we digest food. The process of breaking down food by plants and

animals will be dealt with in a future unit.

Model 3 shows you the recipe for photosynthesis along with a list of the ingredients and their amounts.

This is the way scientists write recipes except they call them chemical equations instead. The top row

shows you the chemical symbols for each ingredient while the bottom row shows you the common name

for them. Study and discuss Model 2 in your groups now.




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Model 3

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16. List the reactants and products from Model 3 in the table below.

REACTANTS PRODUCTS

17. Can you find the ingredient that doesn’t include how much of it to use? Why do you think that is?

18. Is light a reactant or product? Explain your answer.

19.What do you think the big arrow pointing to the right in between Water and Glucose means in

Model 3?

20. Think of our cake example. Can we turn our finished baked cake back into the original ingredients?

Once photosynthesis occurs, do you think it can be undone?

21. Remember the deer in Model 1? Using the chemical formula, which product does the deer use to

breathe?

22. Which product does the deer use for energy?




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23. Which by-product do deer, humans, and many living organisms use to breathe?

You’ve already learned that food can be broken up into 3 main groups: Carbohydrates, proteins, and

fats. We eat carbohydrates for most of our chemical energy needs. Glucose is a carbohydrate,

specifically a sugar carbohydrate. Plants use this sugar as its source of fuel and when we eat plants we

are using them for fuel, too.

HOW DOES PHOTOSYNTHESIS WORK?

Model 4

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Photosynthesis happens in the leaves of the plant. The leaves are a lot like solar catching solar panels.

Sunlight isn’t enough though. Just like a cake requires more than flour, photosynthesis requires more

ingredients. Water is taken up into the rest of the plant parts through the roots and carbon dioxide

enters the bottom of the leaves through mouth-like structures called stomata.

CHLOROPLASTS

Have your group watch the Bill Nye the Science Guy video on chloroplasts to review what you learned

back in 6th

grade using this link: http://www.youtube.com/watch?v=dax7v711qg0.

Model 5


http://www.youtube.com/watch?v=dax7v711qg0



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Inside the leaves the light is moving directly into the green chloroplasts where the sunlight will be

transformed into chemical energy in the form of glucose. This glucose will be used as a source of

energy for the plant itself to perform all of its life functions such as reproduction, growth, and the

making of more food.

In Model 5, the little green oval shaped organelles are the chloroplasts.

Circle the best answer.

24. In what part of the plant does most photosynthesis take place in?

a. The roots

b. The flowers

c. The stem

d. The leaves

25. What structure in plant leaf cells does the light energy transform into glucose (chemical energy)?

a. Cell wall

b. Chloroplasts

c. Nucleus

d. Water vacuole

26. What part of the plant takes in carbon dioxide?

27. How are the processes of photosynthesis and cellular respiration related?

28.VIDEO OPPORTUNITY

In your groups, watch and discuss the video entitled, “The Simple Story of Photosynthesis and Food”

only up to time marker 2:28 with the link http://www.youtube.com/watch?v=eo5XndJaz-Y.


http://www.youtube.com/watch?v=eo5XndJaz-Y

Documents

Photosynthesis From Light to · PDF file... to produce usable chemical energy for their functions. Without organisms that make ... Photosynthesis & Cellular Respiration ... sunlight